JPH07110408B2 - Method of providing extension at end of component and method of providing extension at end of airfoil - Google Patents

Description

Detailed Description of the Invention

[0001]

[Related Patent Application] As an application related to the present application, 1992
Co-pending US Patent Application No. 07/92 dated July 30, 2013
2447, which should be referred to here.

[0002]

FIELD OF THE INVENTION This invention relates to a method of growing an extension at the end of a component having internal passages and unidirectionally oriented microstructures, and more particularly to extending the end to the extension. The present invention relates to a method of growing an extension part and a part extended by the method, as used as a growth seed of the same.

[0003]

2. Description of the Prior Art Techniques for growing unidirectionally oriented structures from a molten bath of a given material have evolved from simple shaped members to complex shaped parts. Among such techniques is the technique of forming directionally solidified alloy parts for use in the hot zone of a gas turbine engine within a complex shaped mold. Documents well known to those skilled in the art disclose numerous examples of components of this type, for example turbine blades and vanes manufactured as described above.

The use of components, such as turbo engine or gas turbine engine blade members, in environments where airborne particles are present, especially in the harsh high temperature oxidizing and / or corrosive conditions found in the turbine section of gas turbine engines. In addition, oxidation, high temperature corrosion, erosion, wear, low cycle fatigue cracking and other damage can occur to these types of parts. Because such parts are expensive to manufacture, it is economically desirable to repair them rather than replace them.

As an example of a complex shaped blade member of the type described above, Ande, assigned to the applicant.
rsen), U.S. Pat. No. 4,010,531 (1977).
There is a turbo engine blade listed on March 8, 2013). Such blades are provided with a complex hollow interior that communicates with the open tip for cooling purposes. By using the above-mentioned known technique, a component such as a blade member can be manufactured as a single crystal or as having a fine structure solidified in the directionality of elongated crystal grains. The combination of casting mold technology and casting method enables such manufacturing. As is well known in the blade member art, the characteristic crystallographic orientation of nickel-based superalloys often used in blade members is <
The 001> crystal direction is substantially parallel to the growth direction. Designers of such blade members take advantage of their characteristic crystallographic orientation to reduce the modulus of elasticity and, therefore, by mechanisms such as thermal fatigue, machine along a particular direction relative to the shape of the component, such as the blade member. The risk of physical damage can be reduced.

[0006]

If a complex shaped part having such a unidirectionally oriented microstructure is damaged during operation or in the course of its manufacture, the problem of repair is required. Becomes more complicated and difficult. This repair problem is typically encountered when attempting to maintain a unidirectionally oriented structure in the repair as well, as is desired for unidirectionally oriented components such as airfoils, including blade members. Is especially important.

[0007]

The present invention, in one form, comprises:
A method of providing an extension at the end of a component is provided. The component has a peripheral cross-sectional shape and at least one passage defined by a hole passing through an end of the component and communicating with the hollow interior of the component, the component further comprising:
It has a unidirectionally oriented microstructure and a superalloy chemical composition. This method of the present invention comprises the steps of providing a molten material having a superalloy chemical composition that matches the chemical composition of the part in a pressure vessel, and a die opening whose cross-section matches the cross-sectional shape of the part. Providing a die having an inner wall having a hollow extension inner wall positioned at a first extension end around the die and an opposite second extension provided in the molten material. Providing a die extension having an end, applying fluid pressure to the molten material so as to force the molten material through the second extension end and into the hollow interior of the die extension, and the end of the part. The part through at least a portion of the die in contact with the molten material and sufficient time for a portion of the end of the part to interact with the molten material as a unidirectionally oriented microstructured growth species. Holds the end of the part in contact with the molten material during And a step of withdrawing the end of the part through a die at a predetermined speed, the predetermined speed being a microstructure formed integrally with the end of the part and oriented in one direction of the part. Is a rate that allows the molten material to solidify unidirectionally in the die onto the growing species as an extension having a substantially continuous crystal structure.

The invention, in another form thereof, provides a method of providing an extension at an end of an airfoil. The airfoil has a base as a first end and an integral airfoil as a second end attached to the base first end, and the second end of the airfoil is provided. The portion has a peripheral cross-sectional shape and at least one passageway defined by a hole passing through the second end of the airfoil and communicating with the hollow interior of the airfoil. The airfoil also has a unidirectionally oriented microstructure and a superalloy chemistry. The method according to the invention comprises the step of providing in the pressure vessel a molten material having a superalloy chemical composition which matches the chemical composition of the airfoil and the peripheral cross sectional shape and cross section of the second end of the airfoil. Providing a die having an inner wall with a die opening, a hollow extended inner wall positioned at a first extension end around the die, and an opposite side provided in the molten material Providing a die extension having a second extension end of the molten extension, and applying a fluid pressure to the molten material so as to force the molten material through the second extension end and into the hollow interior of the die extension. Adding, passing a second end of the airfoil through at least a portion of the die in contact with the molten material, and growing a microstructure in which a portion of the second end of the airfoil is unidirectionally oriented. Enough to interact with molten material as a seed Holding the second end of the airfoil in contact with the molten material for a period of time, and withdrawing the second end of the airfoil through the die at a predetermined rate, the predetermined rate being , The molten material grows in the die as an extension that is integrally formed with the second end of the airfoil and that has a crystalline structure that is substantially continuous with the unidirectionally oriented microstructure of the airfoil. It is the rate that allows solidification in one direction on the seed.

[0009]

In the casting technique, fluid pressure, eg inert gas or air, is added to a molten material, eg metal, in a closed vessel and the molten material is pushed upwards through a tube. . Such a method and associated equipment is described in Woodburn, J.
r.) U.S. Pat. No. 3,302,252 (issued Feb. 7, 1967), which discloses a method and apparatus for continuously casting a part through a casting tube upward into a cooling mold. . The cast parts are continuously withdrawn from the mold.

In other fields of casting technology, EFG (Edge-d
efined, Film-fed Growth) method.
In this method, no external pressure is applied to the liquid material, which relies on capillary action in a narrow forming tube or die to aspirate and solidify the liquid material upwards. In most cases, seed crystals are introduced into the liquid to initiate crystal growth. A representative patent disclosing the characteristics of this type of method is La Belle, Jr., US Pat. No. 347.
No. 1266 (issued October 7, 1969), Asano (As
U.S. Pat. No. 4,120,742 (1978).
October 17, 2007), and Harvey U.S. Pat. No. 4,937,053 (issued June 26, 1990).

In some and other of the aforementioned patents in the casting technique for forming directionally solidified or single crystal parts, seed crystals having a predetermined crystallographic orientation (primary α and / or secondary β orientation) It is used. Such seed crystals constitute a starting means for solidifying a part having a predetermined crystallographic orientation. Hitherto, in order to join components of a single crystal or a directionally solidified elongated crystal grain component such as an airfoil of a turbo engine, a separately cast member having a predetermined crystal orientation is usually used. Such members are assembled along the interface between the members and joined to one piece. Patents relating to this type of joining technology include U.S. Pat. Nos. 3,967,355 and 4,033,792 to Giamei et al.
No. is typical. These patents show attempts to match the crystal structures on both sides of the bonded interface.

The method of the present invention provides a novel combination of steps for casting or growing extensions directly to the ends of existing parts to allow repair. By using the component itself as a seed or starter means, the extension is provided with a crystalline microstructure that is consistent with and continuous (including orientation) with the crystalline microstructure of the original component. In yet another form, the extension has a chemical composition that is generally distinguishable from the chemical composition of the original component end or body from which the extension was grown. As used herein, the term “crystal structure” means any crystal form such as a single crystal, a large number of elongated crystal grains, and the directional orientation thereof. The term "chemical composition" also refers to the overall chemical or alloy composition, as well as precipitates within the crystal structure,
Features such as size, shape, spacing and composition of phases, inclusions, dendrites, etc. are included. For example, Ni (nickel) based superalloys typically contain γ'precipitates, spaced dendrite arms and various other distinguishable phases.
Crystal structure and chemical composition can be determined by chemical or spectroscopic analysis,
And can be determined and identified by well-known and commonly used techniques such as various X-ray and photomicrography techniques. As used herein, the term “microstructure” (also referred to as microstructure, microscopic structure) encompasses both crystal structure and chemical composition.

In the method of the present invention, a separate member is provided as the part extension and the crystallographic orientation of the extension is repaired, as shown in the aforementioned US Pat. Nos. 3,967,355 and 4,033,792. It is not necessary to match the part to be mated and then bond the extension to a predetermined part of the part in the proper orientation. The method of the present invention accomplishes all of these steps in one operation, forming an extension that is integral with the component and of the same orientation. As described in more detail below, the present invention provides an extension to a component having a hollow interior and an opening or passage communicating with the hollow interior through the end of the component, Especially useful.

In one form of the method of the present invention, the use of a sacrificial appendage at the end of the part to be repaired causes the end of the part to interact with the molten material that grows the part extension, eg, reverse melting ( Melt back) to a minimum. Furthermore,
The present invention significantly reduces or eliminates the need for pretreatment or preforming, or material cutting from the ends, as the damaged part ends interact directly with the molten material as in the case of reverse melting.

For the purpose of evaluating the invention, an apparatus of the type shown in FIG. 1 was used. In the present embodiment, a molybdenum resistance heater 12 is provided on a molybdenum canister 10 having a circular cross section (sealed). Canister 10
An alumina melting crucible 14 is arranged inside. Through the top of the canister 10 is positioned a molding member or die assembly, generally designated by the reference numeral 16. In this embodiment, the die assembly 16 is the molding die 1
8 and a die extension 20. Molding die 18 and die extension 20 each have inner walls 22 and 24 defining a hollow interior thereof, respectively.
8 and die extension 20 also have openings for receiving molten material 26 from the melting crucible 14. The molding die 18 and the die extension 20 are made of alumina, which is often used in high temperature casting techniques, and its cross-sectional shape matches the cross-sectional shape of the part to be treated, but it does not necessarily have to be the same. . Die extension 20 is typically formed from, for example, a high purity polycrystalline aluminum oxide (alumina) tube or a single crystal alumina (sapphire) tube commercially available from Saphikon Inc., Milford NH, USA. ing. The molding die 18 is typically a commercially available high purity, low shrinkage short fiber alumina paper sheet material such as Zircar Products, Florida NY, U.
It is formed from type 99W alumina paper commercially available from SA). Alumina cement, for example ZPI-306 alumina cement commercially available from Zirca Products, is used to join (cement) large deformed parts such as lap joints and corners and bends of alumina sheet material. Was used. Alumina cement is a mixture of short alumina fibers and small alumina particles with a small amount of an unspecified organoaluminum compound (probably aluminum diacetate or subacetate) that acts as a binder in the green state. High-purity castable alumina ceramics such as Cotronics Corp., Brooklyn NY, US
A RTC-60 castable ceramic commercially available from A.) was used to form a curved bottom surface for the molten pool in the forming die 18. The air foil die top was formed as follows. That is, the outer wall is formed and joined (cemented) from an alumina paper sheet into a suitable shape, and then a polycrystalline or single crystal sapphire tube is cast with a castable alumina ceramic material in place at the bottom to form an air foil die. The top was formed. The die thus constituted a die extension tube 20 for supplying a shallow reservoir (having a depth of about 0.6 inch) of the desired forming die 18. As a method of manufacturing the die assembly 16 using castable ceramic, the die assembly 16 is cured (cured) overnight in a plastic bag to prevent uneven drying, and then baked out at about 110 ° C (230 ° F) for 2 hours. And then 1000 ° C
The ceramic was completely cured by firing at (1832 ° F) for 1 hour. The molybdenum resistance heater 28 is used for the die 1.
A die assembly 16 is enclosed to help control the state of the molten material 26 as it travels through the hollow interior of 8 and solidifies.

A fluid pressure inlet tube 32, which is connected to a fluid pressure source (not shown), such as argon, for pressurizing the sealed interior 30 of the canister 10 is provided through the wall of the canister 10. ing. A fluid pressure source to sense pressure inside the canister and maintain a desired preselected level of pressure within the canister 10 or to maintain a preselected level of pressure at a desired schedule. Pressure data may be provided to a pressure controller (not shown) for the device. A thermocouple 36 is used for temperature sensing inside the canister 30. Electric power to the resistance heaters 12 and 28 is controlled and scheduled as desired via the furnace temperature controller 38.

The partial cross-sectional view of FIG. 2 is taken along line 2-2 of FIG. The reference numerals in FIG. 2 have the same meanings as the constituent elements in FIG.
8, die extension 20 and die resistance heater 28 are shown. Each of these components has an airfoil-shaped cross-section in FIG. 2 that corresponds to the shape of the airfoil component 40 of FIG. However, it is to be understood that these cross-sections can have any desired shape required for the repair underway. The extension is an air wheel component 40
Growing on top of the solidification interface 42 (see FIG. 1). However, it should be understood that any shape or combination of shapes may be used for such members, depending on the shape of the part to be extended and the desired shape of the extension.

As an example for evaluating the present invention, a turbine blade of a general type gas turbine engine shown diagrammatically in FIG. 3 was used. Such a blade is designated by reference numeral 44.
Includes a base generally indicated at 4, an airfoil generally indicated at 46, and a blade tip 48. The blade has a hollow interior for air cooling, with cooling holes or passages 50 communicating with the hollow, typically labyrinth-like interior. Since such a blade has a directionally solidified microstructure containing a crystal structure such as a large number of elongated crystal grains, it is necessary to make such a microstructure continuous with a repair portion as well. , Damage to the tip 48 is difficult to repair. The present invention is
It allows the growth of extensions on the blade tip that grow from the parent blade tip and have a crystalline structure and chemical composition microstructure that is compatible with the parent blade tip. In this evaluation, the tip portion 48 of the air wheel 46 in FIG. The material from which such blades are cast is a nickel-base superalloy whose nominal composition is 6.15% by weight.
Al (aluminum), 6.35% Ta (tantalum),
4.9% W (tungsten), 2.8% Re (rhenium), 12% Co (cobalt), 6.8% Cr (chromium), 1.5% Hf (hafnium) and the balance Ni (nickel), It consisted of selected trace amounts of alloy additives and inevitable impurities. The microstructure of such cast blades was a large number of elongated grains oriented in one direction.

Similar, but other nickel-based superalloys were placed in the melting crucible 14 in the canister 10 of FIG. 1 and the canister 10 was sealed. The nominal composition of the nickel-base superalloy in the melting crucible 14 is 6.7% by weight.
% Al, 6.2% Ta, 2% Re, 10.5% Co, 1
It consisted of 6% Cr, 1.6% Hf and balance Ni, a small amount of alloy additives selected, and inevitable impurities. The superalloy was melted by a resistance heater 12 in a low oxygen argon atmosphere at a temperature in the range of about 2790 ° F to 2905 ° F. The die assembly 16 including the forming die 18 and the die extension 20 is placed in position as shown in FIG. 1 and the molten metal is added by introducing pressurized argon through the fluid pressure inlet tube 32. Pressed. At a pressure of about 48 inches H ₂ O, the molten metal is transferred to the die extension 20.
It was pushed upward into the molding die 18 inside. About 50.5 inches H ₂ O was sufficient pressure to bring the molten metal 26 into contact with the blade tip 48 and held in this state for about 4 minutes. Meanwhile, the blade tip 48 is
It interacted with the molten metal 26 by reverse melting up to (as indicated by the dashed line 52 in FIGS. 1 and 3). Furthermore, the blade tip 48 acted as an oriented growth seed for the molten metal 26 in the die 18. The airfoil component 40 and component end or blade tip 48 were then withdrawn by moving upwards at a rate of about 0.2 inches / minute as indicated by arrow 54 in FIG. As a result, the blade tip 48
Solidified in the die 18 to grow an extension having a crystal structure of a large number of elongated crystal grains solidified in the same direction as the air-foil blade tip 48. The extension was continuous and integral with the blade tip. Withdrawal and directional solidification continued until about 0.4 inch of extension with the same shape and crystallographic orientation as the blade tip 48 was obtained.

During this process, the die heater 28 was used to control the temperature within the die assembly 16 and the position of the solidification interface 42. A chill, not shown, as is well known and widely used in directional solidification casting technology
Further control of the solidification interface can be achieved by using the same position. Such chills can provide the desired steep thermal gradients for a given solidification and microstructure growth.

Since the die assembly was formed from alumina, variations in melt depth in the airfoil-shaped cross section of the die assembly were observed to be as expected for a non-wetting system. This allowed the growth seed blade tip to be placed in the die such that contact was achieved across the tip from the leading edge to the trailing edge. As shown in the above examples, the composition of the blade tip alloy was different from the composition of the alloy of the extension grown on the tip from the molten metal. However, these two compositions were chosen such that the crystal structure of the extension grew integrally and continuously with the crystal structure of the blade tip, which was the body for the extension.
This growth mode is sometimes called epitaxial growth. In the context of the present invention, this is usually a necessary condition to ensure compatibility between the blade tip (or body) alloy and the extension alloy. Compatibility (coexistence or compatibility) generally refers to the fact that these alloys are mutually contaminated by contamination, liquid metal embrittlement, formation of brittle phases at the interface or otherwise.
Means no adverse effect. Compatibility also means a certain limit in the discontinuity of mechanical properties, physical properties and metallurgical structures between the blade tip and the extension. Ultimately, conformity must be measured by performance. If an extension of one alloy can be repeatedly grown on a part of another alloy, and if the part on which the extension is grown can withstand subsequent manufacturing operations, then also finish If the used parts work well in use, despite the general discussion above,
As an exception, we have to conclude that these two alloys are compatible. The same is true for sacrificial appendages. The expression “molten material conforming to ...” as used herein is understood to mean a material or alloy which, when present in the liquid state, fulfills the aforementioned compatibility criteria.

A component obtained by practicing the present invention includes a body, eg, a parent blade tip, which has an internal passageway and which in the above-described embodiment is unidirectionally oriented. Has a first crystal structure of a large number of elongated crystal grains, and a first chemical composition based on the alloy composition of the main body. The integral and continuous extension of the body has a second crystalline structure which is continuous and compatible with the first crystalline structure of the body, and also has a first crystalline structure of the body. It has a second chemical composition that matches and is compatible with the chemical composition but is distinguishable from the first chemical composition. The interface between the body and the extension differs from the interface obtained by the conventional method of diffusion bonding different mating and separately formed members together. The main difference between the present invention and the conventional method lies in the interface. In the present invention,
The extension is epitaxially grown by sequentially depositing layers of atoms from the liquid material selected as the extension on the surface of the body. Therefore, the crystal structure is continuous on both sides of the interface. Unlike conventional interfacial bonding techniques, where it is difficult to match the secondary grain orientations in the lateral direction, the method of the present invention also allows the secondary grain orientations to grow. Thus, the epitaxial growth region or repair zone matches the original metallurgical grain structure or orientation of the component not only in the primary direction but also in the secondary direction. The advantages over current repair methods with equiaxed grains at the interface and the repair area are significant with respect to mechanical and metallurgical properties.
This is because the metallurgical grain structure of the original part does not match the extension or repair area using conventional methods. Even when different alloys are chosen for the body and extension, there is generally a gradient in the metallurgical structure in the interfacial region as a result of the rapid mixing of atomic species in the liquid adjacent to the solidified structure. Occurs. Even if the conventional method is performed with great care, it is likely that local surface irregularities or small misalignments will occur between the body and other extensions, which are between the two parts. The result is a small angle boundary of the seed. Similarly, contaminants on either component are likely to be trapped at the interface, thereby weakening the joint. Moreover, conventional methods of repairing such parts typically include
There is the drawback that as the molten metal flows into the passage and solidifies, it blocks the passage. This would require additional cutting work to open the passage.

The above-described embodiments have shown that they have the same cross section as the parent airfoil and allow controlled growth of extensions of the type required for repair of airfoil blade tips. Although this embodiment is for one end only, the tip extension, it should be understood that the invention can be extended to repair multiple component ends, eg, multiple blade tips simultaneously. The present invention is
It can also be used to repair other unidirectionally oriented components having passageways, such as air foil vanes.

From this example, it was concluded that the crystal structure of the extension should be substantially the same as the crystal structure of the existing component. However, it has been unexpectedly found that there may be, and in some cases even preferred, significant differences in chemical composition, especially alloy composition, between existing parts and extensions. As a result of practicing the present invention, the airfoil 46 of FIG. 3, as shown in FIG. 4, extends 56 from the dashed line 52 where repair was desired.
Is included. As can be seen from the partial diagram of FIG.
As a result of using the airfoil 46 as a growth seed, an extension 56 having a conformable microstructure, which in this embodiment includes a number of elongated grains, is formed as a continuous and integral part of the microstructure of the parent airfoil. can get.

FIG. 6 is a cross-sectional view of another shape of the tip end portion of the air cooling blade of the gas turbine engine taken along the line 6-6 in FIG. Shown in. This type of tip is sometimes called a "squealer tip". This is because, depending on the operating conditions, the tip may interfere with the opposing member or rub against the member and approach the state of zero clearance.
As a result of such interference, the outer peripheral rim 58 (FIGS. 5 and 6) of the airfoil 60 may be worn or damaged. Even in the absence of such rubbing conditions, particles and oxidation in the air can wear the rim 58 and damage it during long periods of operation. Using the method of the present invention, such damage can be repaired by providing extensions in the manner described in the previous examples. However, if the rim 58 is narrow or the damage extends close to the shelf 62, then the molten material 26 of FIG.
Restricting rim 58 interactions such as reverse melting in
It should be carefully controlled. In one form of the method of the invention, the sacrificial appendage (FIG.
(Reference numeral 64) is used. Rim 5 in Figure 7
The edge or surface 66 of 8 indicates that it has been eroded, damaged and in need of repair.

The sacrificial appendage 64 need not have the same microstructure as the blade tip, eg, many elongated grains or single crystals. All that is required is that the addendum 64 be the rim 58.
Attached to the molten material 26 and formed from a material that is compatible with the molten material 26. For example,
If the molten material 26 is a nickel-based superalloy, the additive 64 can be nickel or the molten material 2
A nickel-base alloy containing an element that does not dilute or substantially change the composition of No. 6, or a molten material 26
The alloying element may be a kind of alloy or the like. The appendages 64 can be provided by various methods known to those skilled in the art, such as flame spraying, electrodeposition, diffusion bonding of preformed members, etc., as long as they do not affect the passage. When the passage is affected, additional work is required to ensure communication with the interior of the part. Also, because the sacrificial adduct 64 dissolves in the molten material 26 when performing the method of the present invention, the shape of the adduct 64 can be any convenient shape. That is, the addenda can be shaped as an extension of the rim 58 as shown in FIG. 7 or can be a shim, sheet or foil supported by the rim 58. When the adduct 64 is melted by the molten material 26, at least the surface microstructure of the rim 58 is melted.
Exposed to No. 6 allows such surfaces to act as growth seeds in accordance with the present invention. The use of the sacrificial appendage 64 facilitates proper positioning of the airfoil component 40 of FIG. 1 so that when a component such as the airfoil 60 of FIGS. 5, 6 and 7 is being repaired, the 7
The reverse melting line 68 of the
Instead of being in 2, it leaves the shelf 62. Without such sacrificial addendum, it may be necessary to reverse melt the rim 58 into the shelf 62 in order to achieve full contact and interaction with the molten material 26.

8, FIG. 9 and FIG. 10 which are schematic sectional views
FIG. 1 shows a series of steps for carrying out the method of the present invention in a surrounding forming die (not shown) as shown in FIG. 1 for repairing a part having a hollow interior. For example, such an interior may be a labyrinth passage 70 in an air cooled turbine blade or vane. For convenience, some of the reference numbers are the same as used in the previous examples. In FIG. 8, the rim 58 is in contact with the molten material 26 and is partially reverse melted by the molten material 26 from the previous rim edge 66 shown in phantom. In FIG. 9, reverse melting (melt back) is further continued, and the remaining portion of the rim 58 is the molten material 26.
It travels in the rim 58 sufficiently to act as a growth seed to reach the reverse melting line 68. Next, the air foil 6
0 is moved upward while maintaining contact with the molten material 26, as indicated by arrow 54 in FIG. Thus
Solidification above the melting line 68 causes the extension 56, bounded by the dashed line 72, to grow on the rim 58.
The fusion line 68 becomes the solidification interface 42 as described above. Depending on the part, if the blade extension 56 is solid, additional holes may be drilled as desired to provide air discharge from the hollow interior or external communication of the hollow interior. For example, such holes can be formed by laser drilling, electrochemical or electrical discharge machining methods, which are well known and commonly used in the material ablation art.

In one example for evaluating the present invention, air cooled turbine blades of the type shown in FIGS. 5, 6 and 7 were used after being placed in gas turbine operating conditions. The blade is formed from the same nickel-base superalloy as in the previous embodiment. This alloy contains Al and Hf in its composition and these elements form stable surface oxides when exposed to the high temperature oxidation state. Such alloying elements, and in some cases yttrium, are commonly used in nickel-base superalloys forming turbine blades. Accordingly, air cooling passages or holes, such as holes 7 in FIGS. 5, 6 and 7.
The exposed surface of 4 is coated with a surface oxide which does not interact with or dissolve in the molten material such as melt 26. Since such a surface is an oxide, it acts as a non-wetting mold. In this example, reverse melting proceeded into the blade material where the holes were formed. Unexpectedly, a molten material 2 having the same composition as the extension material of the previous example.
When contacted with 6, most of the holes were not blocked and the integrity of the holes was maintained. However, in order to avoid such non-wetting effects affecting other parts of a given blade tip that interact with the fused repair material, pretreatments such as mechanical or mechanical removal of oxides, coatings, etc. Chemical surface treatments can be used to promote the growth of component extensions. In one form of the method of the present invention, the fluid pressure applied to the melt is adequate to force the melt into the shaped member, but less than the pressure required to force the melt into the oxide coated holes. Selected as a value. Such pressure limits are a function of hole size.

In accordance with the present invention, a component or member having at least one internal passage is used as a unidirectionally oriented growth seed to match the microstructure of the member at the end of the member. Forming an identifiable extension having a microstructure. Since such an extension is formed from a molten material that is compatible with or compatible with the growing seed material, the extension is integrally formed with the member and It has a fine structure and a continuous fine structure. However, as mentioned above, the composition of the member and the composition of the molten material, and thus of the extension grown from the molten material, need not be the same. For example, the choice of molten material to form a highly environmentally resistant extension is
It relies on an acceptable degree of mismatch in the crystal structure between the member acting as a growth seed and the extension grown from the molten material. The rate of migration of the component end from the molten material, which acts as a growth species, is a function of at least the applied fluid pressure, the temperature of the melt, the thermal gradient at the solidification interface, and the rate of solidification and growth of the extension.

In the method of the present invention, if the melting point of the molten material is lower than the melting point of the end of the component acting as a growth seed, the interaction between the molten material and the growing seed causes the end of the component as a growth seed. Need not be accompanied by a complete melting of. All that is required is that conditions exist at the interface that allow the growth of crystalline structures that progress across the interface and into the molten material.

The invention has been described with reference to specific embodiments thereof, including the embodiments shown in the drawings. However, these examples are illustrative of the invention and are not intended to limit its scope.

[Brief description of drawings]

1 is a cross-sectional view of an apparatus configured to carry out the method of the present invention.

FIG. 2 is a partial cross-sectional view taken along line 2-2 of FIG. 1, showing a cross section of an air-wheel-shaped forming die.

FIG. 3 is a perspective view of turbine blades of an air cooled gas turbine engine.

FIG. 4 is a partial diagrammatic view of a repaired airfoil showing extensions and multiple elongated grains.

FIG. 5 is a partial perspective view of a blade tip portion of an air-cooled gas turbine engine blade.

6 is a partial cross-sectional view of a blade tip portion taken along line 6-6 in FIG.

FIG. 7 is a partial cross-sectional view of the blade tip of FIG. 6, including a sacrificial appendage.

FIG. 8 is a cross-sectional view showing a series of steps for carrying out the method of the present invention on a hollow component.

FIG. 9 is a cross-sectional view showing a series of steps for carrying out the method of the present invention on a hollow component.

FIG. 10 is a cross-sectional view showing a series of steps for carrying out the method of the present invention on a hollow component.

[Explanation of symbols]

 10 Canister 14 Melting Crucible 16 Die Assembly 18 Forming Die 20 Die Extension 26 Molten Material 32 Fluid Pressure Inlet Pipe 40 Air Foil Parts 42 Solidification Interface 48 Tip 56 Extension 60 Air Foil 64 Additive 70 Passage 74 Hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Brian Mc Andrews, Ridgefield Drive, Milford, Milford, New Hampshire, USA, No. 107 (56) References JP 59-47066 (JP, A) ) JP-A-60-250869 (JP, A) JP-B 57-40569 (JP, B2) JP-B 60-47336 (JP, B2) JP-B 58-40641 (JP, B2)

Claims (6)

[Claims] 1. A method of providing an extension portion at an end portion of a component.
The part through the peripheral cross-section and the end of the part.
Is defined by a hole communicating with the hollow interior of the part.
Said at least one passage being
The product also has a unidirectionally oriented microstructure and superalloy chemistry.
And has a superalloy chemical composition that matches the chemical composition of the component.
And the Ru provided molten material being in a pressure vessel process, Ru provided a die around the cross-sectional shape and cross-section has an inner wall having a die opening which meets the component steps, the first around the die Is positioned at the end of the extension of
A hollow extension inner wall and a counter wall provided in the molten material.
Providing a die extension having an opposite second extension end
That step and such that said molten material through said second extension portion end pushed into the hollow interior of the die extension, the molten the steps of Ru added to the fluid pressure to the material, the molten material the ends of said component wherein the step of Ru is passed through at least a portion of the die, the molten material and for a time sufficient to interact as a growth seed microstructure oriented part of the end portion of the component in one direction in contact with between the step of holding the ends of the parts in contact with the molten material, pull disconnect through the die end of the component at a predetermined speed
And the predetermined speed is the same as the end of the component.
Formed in one piece and oriented in one direction of the part
That has a crystal structure that is substantially continuous with the
As a long section, the molten material is deposited on the growing seed in the die.
The part, which has a speed that allows it to solidify in one direction
A step of withdrawing the end of the component through the die and providing an extension on the end of the component. Wherein an end portion of the component prior to passing the die, further the step of fixing the sacrificial addition on an end of the component
And wherein the sacrificial additive comprises a material that is compatible with the molten material and that melts within the molten material to expose a surface of the component to the molten material. The method of claim 1, wherein 3. A peripheral cross-sectional shape, a microstructure oriented in one direction, a hollow interior, and a hole penetrating an end of the component and communicating with the hollow interior. to the end of the alloy part having at least one passageway is defined providing the extension portion, the molten material is an alloy, the fluid pressure in claim 1 are found in addition by gas The method described. 4. The method of claim 1, wherein the walls of the passageway include oxides on the wall that prevent the molten material from interacting with the walls of the passageway. Wherein said fluid pressure applied, the although the molten material is sufficient to pushing into the die opening smaller claim 4 than the pressure required to force the molten material into the passage The method described in. 6. A method of providing an extension at the end of an airfoil.
And the airfoil has a base as a first end.
A second end attached to the base first end
And an integrated air foil portion as an end portion of the
The second end of the airfoil has a peripheral cross-sectional shape and
Hollow out of the air foil through the second end of the foil
At least defined by a hole communicating with the interior
Also has one passage and the air foil further comprises:
It has a unidirectionally oriented microstructure and superalloy chemical composition.
The chemical composition of the superalloy that matches the chemical composition of the airfoil.
The step of providing the molten material in the pressure vessel and the peripheral cross-sectional shape and cross-section of the second end of the air foil are matched.
Install a die that has an inner wall with the die opening
And the step of positioning the first extension end around the die
A hollow extension inner wall and a counter wall provided in the molten material.
Providing a die extension having an opposite second extension end
And the die extension of the molten material through the end of the second extension.
Fluid pressure to the molten material so as to push it into the hollow interior of the part.
Applying force and bringing the second end of the airfoil into contact with the molten material
Passing at least a portion of the die with a portion of the second end of the airfoil being oriented in one direction.
Interacts with the molten material as a growing microstructured seed
The second end of the airfoil for a sufficient time to
Holding the molten material in contact with the die and attaching the second end of the airfoil to the die at a predetermined speed.
In the step of pulling through, the predetermined speed is
Formed integrally with the second end of the airfoil
The air foil has a unidirectionally oriented microstructure and substantially
As an extension having a continuous crystal structure,
The material solidifies unidirectionally on the growing species in the die
The second end of the airfoil, which is a speed that allows
Of the airfoil with the step of pulling through the die
A method of providing an extension at the end.